The biggest fighter on the Mets is the smallest man in the dugout, the 62-year-old manager who scrapped in the bushes for 10 years until he finally was forced to surrender his big-league dream. You admire his fire, the way he cares, the way he smolders and roars when he leads these horses to water and more often than not cannot make them drink, but never stops trying anyway.

Mike Pelfrey, 6-foot-7 Big Pelf, had come up terribly small yesterday, small enough where you — and undoubtedly GM Sandy Alderson — wondered again whether he can be part of the solution around here. Collins needed an iron will from Pelfrey and got an Iron Mike pitching machine instead, and before Fred Wilpon could blurt out “sh***y!”, it was Pirates 7, Mets 0 in the third inning.

You cannot help but view these Mets as little more than club fighters. But sometimes, on days when they take on the personality of their manager, when they get up off the deck for a 9-8 victory, they can feel like heavyweight champions of the world.

You either have a gift to get players to believe or you don’t. Collins has that gift. He has been every bit the teacher and the leader that the Mets craved at this bankrupt juncture in their history.

“It’s his personality, his upbeat personality,” Josh Thole said. “Win, lose or draw, he comes through here and he pats everybody on the back, no matter what. You coulda just thrown the ball into centerfield and they won the game. And he’s gonna stand there and fight for you. He’s gonna come through [the clubhouse] and say, ‘We’re gonna go get ’em tomorrow.’ So when you come to the ballpark with that kind of mentality, you feel like [you have] a chance.”

Then there are occasions when the manager’s spitfire words from a previous night’s disgrace will echo through their ears, and they will listen to them.

“As a manager, sometimes you have to give your team a wakeup call,” Angel Pagan said. ” ‘Hey, we’re better than this,’ and that’s what he did.” Or, as David Wright put it: “Every once in a while you need to be kicked in the rear, and he kicked us.”

Collins will not let the Mets feel sorry for themselves for playing without Johan Santana and Wright and Ike Davis because no one will feel sorry for them anyway.

“He believes in us, and we have to believe in ourselves,” Carlos Beltran said.

Collins had to wait 11 years for another job like this. He lost the Angels’ clubhouse in 1999. He’s even a better communicator now than when Willie Randolph and Jerry Manuel were here.

Yesterday morning Collins explained his ‘We are better than this!’ tirade from the night before.

“They better understand it came from the heart,” he said. “I do not get caught up in who is not here. I get caught up with who is here. . . . And I’ve seen every one of those guys play. . . . I know they can do this. . . . I am who I am. I think I’ve matured through the years of being able to control things a little better. But make no mistake about it — if we played Ping-Pong, I’m gonna try to kick your butt. That fire still burns inside, or I couldn’t be here, I wouldn’t have taken this job.”

The Mets, after Pelfrey’s implosion, took that fire and ran with it. It was Beltran’s three-run home run in the third that further emboldened the Mets.

“I don’t want these guys to play scared, and I hope that’s kinda what they got out of the message [Wednesday] night — ‘Look, I don’t want you looking over your shoulders, like ‘Ohmigod, is he gonna replace me?’ ” Collins said. “What we gotta do is play relaxed, but play with some thought process that’s gonna lead to success.”

The bullpen did its job. Ruben Tejada’s two-out, bases-loaded single ignited the four-run sixth.